Bluetooth on board

Jul 25, 2013

by Fredrick Gary Hareland

GoFree WiFi-1 module

Recently I purchased my first iPad and joined the mobile wireless tablet revolution. Now I wonder how I got along all those years without one of these marvels of modern technology and my wife is wondering why she chided me to get one (she thinks I spend way too much time online!). It truly is a marvelous tool and comes with built-in Wi-Fi and Bluetooth which makes it perfect for getting online in port and for onboard vessel automation, smart energy, entertainment, remote access and control of radar, sonar, depth sounder, and chartplotters. To begin with lets talk a bit about what exactly Bluetooth is and then give an excellent example of how it can be implemented onboard your boat to make life a little easier.

Bluetooth is a wireless technology standard for exchanging data over short distances and was created by telecom vendor Ericsson back in 1994. It basically operates in the same radio frequencies as Wi-Fi (2.45 GHz) but with much lower power output and much shorter ranges. Bluetooth transmits at 1 mW (Class 3), 2.5 mW (Class 2) or 100 mW (Class 1) with subsequent ranges of 1 meter, 10 meters, and 100 meters. A milliwatt is one thousandth of a watt and the most powerful cell phones transmit a signal of 3 watts. This means that the most powerful transmitter output of Bluetooth is just 1/3,000th as much as the cell phone.

The miniscule output of Bluetooth tends to cut down on any radio frequency interference introduced by other electronic devices and yet it still offers a range of at least 300 feet for a Class 1 transmitter. This is sufficient for most recreational boats and all but the longest megayachts. Just as important as low power output is it’s spread-spectrum frequency hopping that cuts down on any interference to other Bluetooth devices. Not to go into too much technical detail, but the transmit frequencies are from 2,400-2,483.5 MHz and there are 79 1-MHz bandwidth channels that the Bluetooth device is hopping between at the rate of 1,600 hops per second. Now that we are squared away with the basic technicalities of Bluetooth, let’s put it to work on board!

We can link our iPad, iPhone or other smartphones with the Simrad NSS7 chartplotter by simply downloading a free app and then installing the Navico GoFree WiFi-1 wireless bridge. This will allow two-way communication between Simrad’s NSS chartplotter and multi-function display (MFD) and your iPad, thus turning the tablet or phone into a mobile remote control station for your chartplotter. The GoFree interfaces with the MFD via an Ethernet connection and the mobile device using Wi-Fi over Bluetooth.

The GoFree WiFi-1 module is very small at 6.75 by 2 by 2 inches and only draws 200 mA at 12 volts or about 1/5th Amp. It has a five-inch omni-directional antenna and once it is mounted securely requires only two cables, one power connected to the 12-volt system and one Ethernet to go to the established Ethernet network. If your setup is not working make sure to check power led and Ethernet led on the wireless bridge. If you have these indications then the app may have been corrupted and needs to be downloaded again. If all else fails go back and read the instructions again to see if you may have overlooked an important step along the way.

This is only one really neat app for boats, but there are many others and half the fun is finding them online. Start by checking the instruction manuals for your boat’s electronic equipment to see if they already have embedded Bluetooth or are Bluetooth enabled. It is a nice convenience to check on things using your portable communications devices while in your cabin or head or galley…you get the idea! Until next time: Blue skies and following seas.